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2 years ago

Which of the following statements describe chemical properties?

Chemistry

1 answer:

Y_Kistochka [10]2 years ago

4 0

Answer:

A. Oxygen gas supports combustion.

B. Hydrofluoric acid reacts with glass.

C. Fertilizers help to increase agricultural production.

Explanation:

Chemical properties can only be observed when a chemical change, i.e. a change in the chemical composition, occurs.

On the other hand, physical properties are observed or measured without altering the composition of the substances.

Typical examples of chemical properties are reactivity, flammability, combustion, oxidation states, acidity, among others that require to carry out a chemical reaction to be observed.

Typical examples of physical properties are freezing point, melting point, boiling point, density, solubility, corrosiveness, among others.

Thus, as for the choices you have:

A. Oxygen gas supports combustion: the only way to observe this property is by carrying out a combustion reaction, so this describes a chemical property.

B. Hydrofluoric acid reacts with glass: again, only by letting hydrofluoric acid react with glass this can be observed, so this is another example of a chemical property.

C. Fertilizers help to increase agricultural production: fertilizers are absorbed by the plants and converted by biochemical reactions, so this also describes a chemical property.

D. Water boils below 100°C on top of a mountain: boiling is a change of state, the water is H₂O and continues having the same composition after boiling, so this describes a physical property.

E. Lead is denser than aluminum: density is measured by physical media, measuring mass and volume; so this is a physical property.

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During a titration the following data were collected. A 10. mL portion of an unknown monoprotic acid solution was titrated with

Liula [17]

Answer:

8.0 moles

Explanation:

Since the acid is monoprotic, 1 mole of the acid will be required to stochiometrically react with 1 mole of NaOH.

Using the formula: $\frac{concentration of acid X volume of acid}{concentration of base X volume of base} = \frac{mole of acid}{mole of base}$

Concentration of acid = ?

Volume of acid = 10 mL

Concentration of base = 1.0 M

Volume of base = 40 mL

mole of acid = 1

mole of base = 1

Substitute into the equation:

$\frac{concentration of acid X 10}{1.0 X 40} = \frac{1}{1}$

Concentration of acid = 40/10 = 4.0 M

To determine the number of moles of acid present in 2.0 liters of the unknown solution:

Number of moles = Molarity x volume

molarity = 4.0 M

Volume = 2.0 Liters

Hence,

Number of moles = 4.0 x 2.0 = 8 moles

8 0

2 years ago

If 25.0 g of NH₃ and 45.0g of O₂ react in the following reaction, what is the mass in grams of NO that will be formed? 4 NH₃ (g)

Allisa [31]

Answer:

The correct answer would be : 33.8 g

Explanation:

Molar mass of ammonia,

Molar Mass = 1* Molar Mass(N) + 3* Molar Mass (H)

= 1*14.01 + 3*1.008 = 17.034 g/mol

mass(NH3)= 25.0 g (given)

number of mol of NH3,

n = mass of NH3/molar mass of NH3

=(25.0 g)/(17.034 g/mol)

= 1.468 mol

Now,

Molar mass of O2

= 32 g/mol

mass(O2)= 45.0 g

similar as ammonia

n (O2)=(45.0 g)/(32 g/mol)

= 1.406 mol

Balanced chemical equation is:

4 NH3 + 5 O2 ---> 4 NO + 6 H2O

1.83456 mol of O2 is required for 1.46765 mol of NH3

by the calculation we have only 1.40625 mol of O2

Thus, the limiting agent will be - O2

now the Molar mass of NO,

= 1*14.01 + 1*16.0

= 30.01 g/mol (similar formula used for NH3)

Balanced equation :

mol of NO formed = (4/5)* moles of O2

= (4/5)×1.40625 (from above calculation)

= 1.125 mol

mass of NO = number of moles × molar mass

= 1.125*30.01